Face masks have been shown to be effective in filtering viruses like the one that has haunted us for many months, the SARS-CoV-2 virus, thus reducing the risk of infection. Now, a team of researchers from the Massachusetts Institute of Technology (MIT) now hopes to go one step further with the design of a mask that inactivates viruses using exclusively heat.
The researchers aim to build masks that incorporate a heated copper mesh that runs on a battery and is surrounded by insulating neoprene. As the person wearing the mask inhales and exhales, the air repeatedly flows through the mesh and the viral particles in the air slow down and become inactivated due to the mesh and high temperatures. Such a mask could be useful for both healthcare professionals and the general public in situations where social distancing is difficult to respect, such as on a bus, a healthcare environment, or the subway.
“The vast majority of current masks work by filtration, filtering particles by size or electrical charge,” explains chemical engineer Samuel Faucher, co-author of the study.
“ This is a completely new mask concept in the sense that it does not primarily block the virus. In fact, it allows the virus to pass through the mask, but it slows it down and inactivates it, “says Michael Strano, Carbon P. Dubbs professor of chemical engineering at MIT and author of the work published in BioRxiv.
How does it work
The experts created mathematical models to determine the optimal temperature range that the mask mesh should reach to thermally inactivate the coronavirus particles as they are inhaled or exited from the mask . They determined that a temperature of around 90 ° C can reduce the viral concentration in the air by a factor of a thousand to a million , depending on the size of the mask.
They also showed that this temperature can be achieved by passing an electric current through a 0.1-millimeter-thick copper mesh or a thermoelectric heater, powered by a small battery.
As the person wearing the mask inhales and exhales, the airflow is continuously reversed, allowing any virus to pass over the mesh many times, increasing the likelihood that it will be inactivated. Purified air comes out of the vents on both sides of the mask.
It’s time to test prototypes
Experts, who have already applied for a patent on the design, have started building prototypes of this mask and hope to start testing them soon. That is, if it is marketed, as the device works with batteries (current prototypes include a 9-volt battery) , it would be more expensive than acquiring a cloth, surgical mask or an N95 respirator, the researchers clarify.
One of the good things about this MIT mask is that it also doesn’t need to be discarded or sterilized after use.
“Of course, we must be mindful of the safety and comfort of mask wearers,” says Faucher. “The air will be cooled after viral inactivation to make the mask comfortable and safe to use.”
“What we show is that it is possible to wear something on your face that is not too uncomfortable, which can actually allow you to breathe medically sterile air,” Strano clarifies. “The prospect of being able to breathe medically sterile air and exhale medically sterile air, protecting the people around you and protecting yourself, is just the next step.”
Reference: MIT NEWS OFFICE / The research has been published on a prepress server, BioRxiv, but has not yet been reviewed by scientific experts.
